Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Quais cartões amarelos têm uma temporada de 1999/2000?
 ###Tabelas: CREATE TABLE nonstructural_viral_proteins (nonstructural_viral_proteins_id AUTO_INCREMENT PRIMARY KEY, RNA Segment (Gene) INT, Size ( s base pair ) INT, Protein VARCHAR, Molecular weight kDa VARCHAR, Location VARCHAR, Copies per particle VARCHAR) CREATE TABLE national_championships (national_championships_id AUTO_INCREMENT PRIMARY KEY, Year INT, Champion VARCHAR, Score VARCHAR, Runner-up VARCHAR, City VARCHAR, Arena VARCHAR) CREATE TABLE current_medical_schools_in_the_caribbean (current_medical_schools_in_the_caribbean_id AUTO_INCREMENT PRIMARY KEY, Country/Territory VARCHAR, Established INT, Degree VARCHAR, Regional/Offshore VARCHAR, IMED/Avicenna Listed VARCHAR) CREATE TABLE career_stats (career_stats_id AUTO_INCREMENT PRIMARY KEY, Season VARCHAR, Games INT, Yellow Cards INT, Red Cards INT, Average Cards a game INT) CREATE TABLE pro-am_event_finals:_5_4_titles_1_runner-up (pro-am_event_finals:_5_4_titles_1_runner-up_id AUTO_INCREMENT PRIMARY KEY, Outcome VARCHAR, Year INT, Championship VARCHAR, Opponent in the final VARCHAR, Score VARCHAR)  
SELECT AVG Yellow Cards FROM career_stats WHERE Season = 1999/2000